Mining The Moon: Closing The Business Case

I recently read Platinum Moon by Bill White, in just 4 days, it's just that much of a page-turner. Clark Lindsey has written an extensive review, which is mostly positive but has this little dig at the end:

A kilogram of pure platinum today sells for something like $53,000/kg. On the Moon even rich PGM ore would have have to be extensively refined to get anywhere close to that purity. A kilogram of raw ore would be worth a tiny fraction of that.

Until there are fully reusable vehicles flying frequently enough to LEO to bring costs there down to the low hundreds of dollars per kg, it's difficult to see how space mining can even begin to be viable.

My first reaction is to suggest that obviously high purity enrichment of platinum should be done on the Moon, and only "pure platinum" returned to the Earth - but I should first point out that Platinum Moon made the realistic argument that lunar platinum would be worth a lot more than market value in the form of commemorative coins and other trinkets - at least initially.

Extraction of oxygen from lunar regolith is a critical part of the plot in Platinum Moon and it's not unreasonable to expect a platinum enrichment facility to be capable of doing it as a side process. Similarly, extraction of aluminum from lunar regolith is an easy process which would also be available. Spinning that aluminum into tanks is simple manufacturing that could be done in-situ, and during lunar night the oxygen would naturally liquefy to make filling easier.

The landing vehicles in Platinum Moon use the fuel RP-1, a form of kerosene which is often approximated as dodecane in chemical formulas - this means it has 12 carbon atoms and 26 hydrogen atoms per molecule. On the Moon, carbon is about as rare as hydrogen, and the biggest deposits are in cold traps at the lunar poles. A simpler hydrocarbon, with higher performance, is methane with just 1 carbon atom and 4 hydrogen atoms. Liquid hydrogen could also be used as a fuel for a reusable lander. It seems inevitable that a complete propellant production plant - both fuel and oxidizers - would be an early infrastructure goal of an operational lunar platinum mine, but it would likely be separated from the mining and refining sites; requiring suborbital hops to refuel.

Estimating the size of a propellant production facility is difficult at this time. Current NASA estimates for a "pilot demonstration" plant to produce oxygen from lunar regolith are in the ~300kg range, producing up to 500kg/year. A similar sized plant in a cold trap could be expected to produce thousands of times as much, and would more likely be bound by the availability of tanks; which I imagine being transported from the distant platinum enrichment facility.. whether local production of tanks is more efficient depends on the flight rates.

Sticking with the "gateway" architecture presented in the book, lunar production of both fuel and oxidizer is game changing. Launching fuel for Earth departure stages from stockpiles on the lunar surface, via EML1, is cheaper than launching from Earth's deep gravity well. Storage of cryogenic propellants in the cold traps of the Moon until needed brings just-in-time delivery economics to spaceflight. This would allow the launch of larger processing plants and more sophisticated mining vehicles that can increase the production in a virtuous cycle.

If one could obtain pure platinum from the surface of the Moon, would it be profitable to return it to Earth at current market prices? I've previously shown that the SpaceX Dragon has a downmass of 3000kg at $28,330/kg, returning pure platinum from LEO at a profit of $24,670/kg. With the architecture described, cislunar transport is essentially free, but to make a profit, the initial costs of the architecture have to be amortized over every kg returned.

If the architecture costs low billions to setup then around 100,000kg needs to be returned over several years. For comparison, only 239,000kg of platinum was sold in 2006. The initial premium for lunar platinum would quickly fall to market levels, but would the market value of platinum fall significantly thereafter? I have had long arguments over whether or not platinum is an elastic market that is significantly effected by the opening of a new mine.. it's simply not clear what the demand for platinum is because the supply is so low at present, but it should be clear to see from the growing price of platinum over the years that more and more demand is out there for a very limited supply.


  1. Anonymous7:26 PM

    "Liquid hydrogen could also be used as a fuel for a reusable lander."
    And IIRC there are new studies based on a LOX/ nano-particulate Al monopropellant that could bear fruit.
    (Sorry cant find reference :(
    Lunar Hydrogen is just too valuable just to throw it away... Indeed its value in the form of water exceeds that of platinum. Platinum is not much good at supporting life or is as an effective radiation shield.

    Whilst a Platinum Moon Mint might make money; I think that just plain rocks, imbedded in lunar glass may have a more immediate 'value' to collectors and the idle rich. The industrial process is (probably) more simple and can be achieved without the need for extensive: exploration, excavation and extraction.

  2. thanks brobof, read any development on Al/LOX rockets? If it's possible it would certainly be valuable.

  3. brobof, you might like this:

  4. .

    the "precious metals" are "precious" and high priced, since rare

    if a precious metal become common like the iron, its price falls

    and, with a falling price, it's no longer a good business extract it

    not if extracted on Earth and not even on the Moon or asteroids

    extract water and materials on the Moon for ISRU is a different story

    but, again, it will be a good choice, only when ISRU costs will be low


  5. Phillip5:58 AM

    Supply side eco 101--yes if supply is high price will fall eventually..but if even if the supply is doubled price might full..but now there may be more demand at the lower price so that in the end you can end up making even more money. Eg--I can only supply 1 ton of platinuim at $1m and demand is for 2 tons. The most I can make supply is 1 ton and and make $1m. Now if I can supply 2 tons--I may make $2m. Evenually the price "might" fall to 0.5 ton/million. But if can supply 4 tons..the demand might leap to 20 tons/year--now I am supplying 4 tons and now the cost per ton is 0.75 but now I am making $3m/year.

  6. Trent, this is what I wrote for the Space Review on this topic (several years ago):

    "Priming the pump for lunar PGM mining"

  7. Anonymous10:08 AM

    Some college kids just launched an nanoparticle alox solid rocket. think i saw it on Science News site.
    Think it is a midwest university

  8. My last paragraph there really is trying to make the case that you don't need to upset the supply side of the platinum market to close the business case for mining. If you're returning 10,000kg for 10 years, that's only 4.18%/year of the world market. I expect, even if you doubled that rate, traders would declare it a non-event.. on par with a slight expansion of an existing mine.

  9. Anonymous, solids are interesting, Al/Ice is not that interesting. That paper I linked has 3 Al/LOX designs, a liquid metal biprop, a hybrid and a mixed monoprop. The hybrid is probably the most feasible for ISRU, and it looks like no-one has ever built one.

  10. Bill, the best part of the article is the bio at the end. What's 5 years between friends? :)

  11. great post thanks for this info but i have a question about this topic can you tell me some information about silica.

  12. Anonymous12:04 AM

    While I want to see the moon and other places become part of the economic whole I don't think it's going to be easy.
    Every screw, spanner and nut will have to be imported from earth.
    A simple factory has tons of stuff in it. And there is the need for a constant flow of spare parts because things inevitably break.
    Look at the mass of a simple mining steam shovel!
    Sure you can build a small demo plant of a few kilograms and ship that to the moon, but for a serious mining venture....?
    And the moon - to be really economic is going to need hundred of factories/mines. All different.
    That's an incredible ammount of mass.
    Bringing all that mass up from earth is not going to be possible for a very long time.
    It seems to me that you really need to develop bootstrap technologies. From things like print manufacturing up to Von Neumann self replicating machines.
    And before that even more primitive machines.
    Start simple.
    Forget PGM's or even oxygen processing or making RP1, or methane.
    The first thing you need on the moon is a man with a spanner.

  13. > Launching fuel for Earth departure stages
    > from stockpiles on the lunar surface, via
    > EML1, is cheaper than launching from Earth's
    > deep gravity well.

    Really? That’s never been true in the past (quite the opposite). A lot of folks assume the lower Delta-V proves lower launch cost, but with delta-V having virtually no impact on Earth launches (To Quote Elon Musk “the Delta-V is free.”).

    Certainly dropping that ISRU dev effort, and instead focusing on better transport ships would pay more dividends? After all you must first develop a new Earth, to orbit, to Luna, space infrastructure just to set up and operate anything on the moon. Assuming you kept in mind your fuel to space goals in mind (and cargo from Luna to Earth goals), a integrated single transport system fueled from Earth, would be cheaper in any realistic near future scenario then ISRU I can think of.

  14. Obviously I'm assuming no change in current launch prices Kelly. If you anticipate a future where cheap access to space comes into full effect then setting up an in-space architecture is only a marginal improvement. But why is it you're allowed to anticipate CATS as a "realistic near future scenario" when decades of effort in that direction have yielded nothing?

  15. CATS is technically easy, but doesn't save any money with the current scale market. A mining op on on the moon is a much bigger Market. Also give launch from the moon traditionally costs more then launch from the Earth to GEO/LLO -ISRU doesn't help.

  16. For a bunch of numbers I doodled with on this this afternoon.
    Given it sounds like you’re talking about transporting at least ten tons of Material from Luna to Earth per year – you need a pretty good transport system in the first place! Say 3 ton cargo capacity Luna to Earth system.

    If you Assume no aero braking, and instead meet a different craft in Leo, you need a 6.4 Km/S delta-v craft to getyou from Lunar surface to LEO – and some way to fix it for reflight back to Luna surface for the next bit of cargo. (At the least you’d need on orbit refueling.) Really it makes more sense to aerobrake and land. It cuts your delta-V from Lunar surface back to LEO (or reentry) to 3.2 Km/S, and eliminates a separate on orbit servicing issue, and a need for a second ship to bring down the cargo.

    Assuming Lunar launch to Landing on Earth reusable like a X-37 like drone.
    15 ton freighter,
    30 tons LOX/RP for the return flight with aerobraking.
    3 tons cargo

    Then of course you need to send it back to the lunar surface. If you assume you need to land it with its return RP (8 tons ish) but no LOx or cargo, you need another 135 tons of LOx/RP to boost it out from LEO, and you need to build, field, and service on Luna LOx recovery and refueling (reLoxing?) facilities. And you’ll need to lift a total of 496 tons to low Earth.

    Or you could just add more LOx at LEo. You’ll need 270 ton’s of LOx/RP in the craft to boost it from LEO to, and land on, the moon; carrying all the LOx and RP (30 tons) it will need to fly and land back on Earth with 3 tons to cargo. And you’ll need to lift a total of 653 tons to low Earth. 32% more lift to LEO. Lifting 32% more to LEO isn’t really a cost increase. Virtually all launch costs are fixed costs, so more flights doesn’t increase your cost per year.

    Your able to lift everything with existing LVs … sort of. The round trip ship is 15 tons or so dry but even if you assume on lunar surface reLOx’ing, you’ll need a total of 496 tons to orbit, not including tanks, and equipment to bring it to a on orbit depot. That’s 17 flights to LEO per fight to the moon. Assuming you’re going to want 4 cargo flights per year from the moon, plus fights to the moon to supply the surface mining gear, your likely over a hundred launches per year – likely beyond any current launchers capabilities. With no ISRU, its 22 launches per lunar fight – which doesn’t make it much worse.

    Eiather way, you really should looking going to need far too many launches for any current system. It took 45 years for the Russians to launch 100 Soyuz, it would take 23 years to launch 100 shuttle flights at ave flight rates. You need that much a year. So you need your own launcher.

    Being cheap, if possible you’d like a avoid extra costs, and since you’re already stuck with a building a reusable Lunar to Earth craft, making it do double duty would save a lot of dev costs. Said Luna to Terra craft likely drops some tanks on route to Luna (with no Lunar reLOxing it would leave LEO with with a mass ration of 14), and really wouldn’t need to have a thrust to weight ratio a Earth to LEO craft would generally have – but upgrading for that isn’t going to up your dev costs much. Say its reaction mass ratio with 10 tons of cargo is 6. Use two of them belly to Belly as a biamese and it would put 1 into orbit with said cargo. Course you’ll need 27 flights with 10 tons of fuel to fuel your stack in orbit for the Lunar flight, but in principle that’s not that hard to design the craft to do, with no impact of its Lunar recovery mission abilities; and that’s likely cheaper then developing a fuel HLV.

    Again given the bulk of launch costs (high 90%tile) are fixed, the increased flight rate won’t dramatically increase your yearly budget. Launching a biamese stack with a unfueled weight of 50 tons shouldn’t be bad. Given DC-X serviceability, a staff of 50 could turn it around for relaunch in 24 hours if necessary.

  17. Anyway, say $2B to develop said automated craft (DC-X folks were projecting $5B [now year money] to get a certified DC-X derived 20 ton cargo capacity SSTO RLV in production – so $2B for this seems in the ball park), and your lifting your supplies to a LEO staging area, and lifting the craft with cargo to be refueled/reLOxed in LEO for a flight to the lunar surface to pick up and return your 3 tons of cargo? Over a hundred launches from Earth per year. Couple hundred million a year for ground support, fuel, etc. Labor per launch $100K-$150K? Cost per launch over 10 years $4 million? $200 per pound to orbit, $19,000 a pound returned to Earth? [Not including production cost of ships (tens of millions per?) and the durability of ships and parts.]

  18. long post is long.. why not write it up and post it on your own blog Kelly? :)

  19. Don't got a blog.

    Got a book on stuff like this I'm working on - hopefully it will be a better use of my time.


  20. I've had that book on my kindle for a couple weeks. I think I shall start to read it now :-)

  21. > QuantumG said...

    > Obviously I'm assuming no change in current launch prices Kelly. …

    Really, isn’t that the most unlikely assumption in the scenario? It’s like assuming no changes in freight prices to some place after a rail road line goes there, or no change in ticket prices to Miami in December.

    Any huge jump in traffic always lowers costs, and this project certainly assumes historically huge launch rates and tonnage to LEO and Luna. So the lunar mining project would force global launch costs down – and be in a ridiculously good position to get lower launch prices out of vendors.

    Also frankly since you couldn’t use any current system for a project like this, you’d likely order a lost cost one – which certainly most of the usual suspects have long offered.

  22. Anonymous7:09 PM

    That was enlightening.


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